Stating your personal plans to everyone can make you stress out more if you get a rough start. It can be demotivational if you think that people no longer expect you to commit to a routine or diet. You can set yourself up for failure or stay true to yourself.
This TED talk cites several studies and argues the theory that you are actually less likely to achieve a goal if you talk about it with others. The theory is that by telling others your plans, their praise and support falsely make you feel like you’ve already achieved or worked toward your goal, and so you’re not going to work toward it quite as much.
I’ve always been conservative about sharing my personal goals. But this is because I dislike forming or living up to others’ expectations – I’ve always had a bit of a rebellious personality. Similarly, however, I’m hesitant to have long-term expectations from others and, therefore, rely on myself to attain the goals. For example, although I did P90X with my husband for a couple of rounds, which was motivational most of the time, on other days, when he decided to do something else, I held on to the workout routine that I had committed myself to doing. I still shared my plans with a couple of close friends, and eventually the people in my daily life all figured out that something was up as my routines changed etc., but I never posted my commitment, nor achievements, to Facebook.
Perhaps you disagree with the studies and TED talk, and maybe they didn’t research long-term goals specifically, but it is important to be aware of the expectations you set. I know many people who are consistently setting goals but never actually committing to them. One reason for this is that people get discouraged by hard work, that they don’t realize the magnanimity of the commitment they’re making or that they’re not specific enough to attain. Be careful of such pitfalls and work around them: for example you can set goals that build on each other so that you build a realistic short-term game plan into your schedule to gradually achieve a big dream.